Add optional metadata param maxLen for redis stream PubSub component (#835)

* Add optional metadata param maxLen for redis stream PubSub component

* fix fmt

* fix error info

Co-authored-by: Phil Kedy <phil.kedy@gmail.com>
Co-authored-by: Dapr Bot <56698301+dapr-bot@users.noreply.github.com>

pubsub/redis/metadata.go

@@ -70,4 +70,7 @@ type metadata struct {
 	queueDepth uint
 	// The number of concurrent workers that are processing messages
 	concurrency uint
+
+	// the max len of stream
+	maxLenApprox int64
 }

pubsub/redis/redis.go

@@ -43,6 +43,7 @@ const (
 	redeliverInterval     = "redeliverInterval"
 	queueDepth            = "queueDepth"
 	concurrency           = "concurrency"
+	maxLenApprox          = "maxLenApprox"
 )
 
 const (
@@ -101,7 +102,7 @@ func parseRedisMetadata(meta pubsub.Metadata) (metadata, error) {
 
 	if val, ok := meta.Properties[redisType]; ok && val != "" {
 		if val != NodeType && val != ClusterType {
-			return m, errors.New("redis type error: unknown redis type")
+			return m, fmt.Errorf("redis type error: unknown redis type: %s", val)
 		}
 		m.redisType = val
 	}
@@ -288,6 +289,14 @@ func parseRedisMetadata(meta pubsub.Metadata) (metadata, error) {
 		}
 	}
 
+	if val, ok := meta.Properties[maxLenApprox]; ok && val != "" {
+		maxLenApprox, err := strconv.ParseInt(val, 10, 64)
+		if err != nil {
+			return m, fmt.Errorf("redis streams error: invalid maxLenApprox %s, %s", val, err)
+		}
+		m.maxLenApprox = maxLenApprox
+	}
+
 	return m, nil
 }
 
@@ -370,6 +379,7 @@ func (r *redisStreams) Init(metadata pubsub.Metadata) error {
 func (r *redisStreams) Publish(req *pubsub.PublishRequest) error {
 	_, err := r.client.XAdd(&redis.XAddArgs{
 		Stream:       req.Topic,
+		MaxLenApprox: r.metadata.maxLenApprox,
 		Values:       map[string]interface{}{"data": req.Data},
 	}).Result()
 	if err != nil {

pubsub/redis/redis_test.go

@@ -40,6 +40,7 @@ func getFakeProperties() map[string]string {
 		poolTimeout:           "1s",
 		idleTimeout:           "1s",
 		idleCheckFrequency:    "1s",
+		maxLenApprox:          "1000",
 	}
 }
 
@@ -74,6 +75,7 @@ func TestParseRedisMetadata(t *testing.T) {
 		assert.Equal(t, 1*time.Second, m.poolTimeout)
 		assert.Equal(t, 1*time.Second, m.idleTimeout)
 		assert.Equal(t, 1*time.Second, m.idleCheckFrequency)
+		assert.Equal(t, int64(1000), m.maxLenApprox)
 	})
 
 	t.Run("host is not given", func(t *testing.T) {